Preparation of Conjugated Aromatic/Heteroaromatic Oligomer-Containing Dielectric Polymers and Their Applications

ABSTRACT

A π-conjugated aromatic/heteroaromatic oligomer-containing vinyl monomer is generally provided, which can include a polymerizable group, a linker group, and a π-conjugated aromatic/heteroaromatic side chain. The π-conjugated aromatic/heteroaromatic side chain includes a first cyclopentadiene ring covalently attached to the linder group, a set of second cyclopentadiene rings covalently attached to the first cyclopentadiene ring, and a third cyclopentadiene ring positioned at a terminal end of the π-conjugated aromatic/heteroaromatic side chain such that the set of second cyclopentadiene rings is positioned between the first cyclopentadiene ring and the third cyclopentadiene ring. Methods are also provided for forming a polymer via polymerizing the π-conjugated aromatic/heteroaromatic oligomer-containing vinyl monomer, and for grafting a π-conjugated aromatic/heteroaromatic oligomer-containing polymer onto a surface of a nanomaterial.

PRIORITY INFORMATION

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 61/755,155 titled “Preparation of ConjugatedAromatic/Heteroaromatic Oligomer-Containing Dielectric Polymers andTheir Applications” of Tang, et al. filed on Jan. 22, 2013, thedisclosure of which is incorporated by reference herein.

GOVERNMENT SUPPORT CLAUSE

This invention was made with government support under N000141110191awarded by the Office of Naval Research. The government has certainrights in the invention.

BACKGROUND

Polythiophenes, oligothiophenes and their functional derivatives haveattracted much interest and have been among the most frequently usedπ-conjugated materials as active components in organic electronicdevices and molecular electronics, including in devices such as OLEDs,OFETs, OPVs and chemo/biosensors. Among thiophene-based polymericmaterials, oligothiophene moieties are generally placed in themain-chain architecture. For example, poly(3-alkylthiophene) (P3ATs) andtheir derivatives are one series of the most developed main-chainthiophene-based polymeric materials, which show very promisingoptoelectronic properties and great potential in OFET and OPVapplications. Compared with the main-chain thiophene-based polymers,side-chain oligothiophene/its derivatives-containing polymers have beenmuch less explored. Though synthesis for methacrylate withterthiophene-containing side-chain was reported previously, mostside-chain π-conjugated aromatic/heteroaromatic oligomer-containingvinyl monomers haven't been synthesized, and especially, polymers basedon such aromatic/heteroaromatic oligomer-containing monomers, includingmethacrylate with terthiophene-containing side chain, haven't beeninvestigated yet by using controlled/living radical polymerizationmethods, for example, reversible addition fragmentation transfer (RAFT)polymerization. Moreover, there are few reports on the potentials ofsuch side-chain aromatic/heteroaromatic oligomer-containing polymers inorganic optoelectronic devices and molecular electronics, in particular,their applications in capacitors haven't been studied yet. Compared withmain-chain P3AT polymers, it is much easier to tune the polymerstructures of side-chain polymers by changing the monomer structures.

As such, a need exists for methods of preparing, via controlled methods,a side chain side-chain aromatic/heteroaromatic oligomer that has apolymerizable group for further polymerization.

SUMMARY

Objects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

A π-conjugated aromatic/heteroaromatic oligomer-containing vinyl monomeris generally provided, along with methods of their methods of formation.In one embodiment, the π-conjugated aromatic/heteroaromaticoligomer-containing vinyl monomer comprises a polymerizable group, alinker group, and a π-conjugated aromatic/heteroaromatic side chain. Thepolymerizable group can include a vinyl group, and the π-conjugatedaromatic/heteroaromatic side chain can include a first cyclopentadienering covalently attached to the linder group, a set of secondcyclopentadiene rings covalently attached to the first cyclopentadienering, and a third cyclopentadiene ring positioned at a terminal end ofthe π-conjugated aromatic/heteroaromatic side chain such that the set ofsecond cyclopentadiene rings is positioned between the firstcyclopentadiene ring and the third cyclopentadiene ring. The firstcyclopentadiene ring can have a substituted or unsubstituted firsthetero-atom substituted therein. The set of second cyclopentadiene ringscan include a number (n) of repeating second cyclopentadiene ringscovalently bonded together in a chain, with n being an integer of 1 toabout 25, with each of the second cyclopentadiene rings having asubstituted or unsubstituted second hetero-atom substituted therein.Finally, the third cyclopentadiene ring can have a substituted orunsubstituted third hetero-atom substituted therein.

A method is also generally provided for forming a polymer viapolymerizing the π-conjugated aromatic/heteroaromaticoligomer-containing vinyl monomer, such as described above, via acontrolled/living radical polymerization method.

A method is also generally provided for grafting a π-conjugatedaromatic/heteroaromatic oligomer-containing polymer onto a surface of ananomaterial. In one embodiment, the method can include polymerizing(e.g., via a free radical polymerization or a controlled/livingpolymerization method) the π-conjugated aromatic/heteroaromaticoligomer-containing vinyl monomer, such as described above, in thepresence of an anchored nanomaterial, wherein the anchored nanoparticlecomprises an anchoring group attached the surface of the nanomaterial.

Other features and aspects of the present invention are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof to one skilled in the art, is set forth moreparticularly in the remainder of the specification, which includesreference to the accompanying figures, in which:

FIG. 1 a shows an exemplary π-conjugated aromatic/heteroaromaticoligomer based vinyl monomer having a methacrylate polymerizable group;

FIG. 1 b shows an exemplary π-conjugated aromatic/heteroaromaticoligomer based vinyl monomer having an acrylate polymerizable group;

FIG. 1 c shows an exemplary π-conjugated aromatic/heteroaromaticoligomer based vinyl monomer having a styrene polymerizable group;

FIG. 1 d shows an exemplary π-conjugated aromatic/heteroaromaticoligomer based vinyl monomer having an acrylamide polymerizable group;

FIG. 1 e an exemplary π-conjugated aromatic/heteroaromatic oligomerbased vinyl monomer having a norbornene-type polymerizable group;

FIG. 2 a shows an example of preparation of a π-conjugatedaromatic/heteroaromatic oligomer-containing methacrylic monomer,2(2,2′:5′,2″-terthien-5-yl)ethyl methacrylate (TTEMA) and an exemplarycorresponding homopolymer;

FIG. 2 b shows an example of preparation of a π-conjugatedaromatic/heteroaromatic oligomer-containing norbornene monomer,2(2,2′:5′,2″-terthien-5-yl)ethyl norbornenate (TTENB) and an exemplarycorresponding homopolymer;

FIG. 3 shows an example of a side-chain π-conjugatedaromatic/heteroaromatic oligomer-containing block copolymer prepared bycontrolled polymerization of TTEMA and styrene;

FIG. 4 shows the relative permittivity versus frequency for exemplaryπ-conjugated aromatic/heteroaromatic oligomer-containing homopolymers;

FIG. 5 shows the loss tangent (dielectric loss) versus frequency forexemplary π-conjugated aromatic/heteroaromatic oligomer-containinghomopolymers; and

FIG. 6 shows an exemplary method of preparation of surface-initiatedpolymerization of a π-conjugated aromatic/heteroaromaticoligomer-containing methacrylic monomer,2(2,2′:5′,2″-terthien-5-yl)ethyl methacrylate (TTEMA), onto a BaTiO₃nanoparticle.

DEFINITIONS

As used herein, the term “polymer” generally includes, but is notlimited to, homopolymers; copolymers, such as, for example, block,graft, random and alternating copolymers; and terpolymers; and blendsand modifications thereof. Furthermore, unless otherwise specificallylimited, the term “polymer” shall include all possible geometricalconfigurations of the material. These configurations include, but arenot limited to isotactic, syndiotactic, and random symmetries.

The term “organic” is used herein to refer to a class of chemicalcompounds that are comprised of carbon atoms. For example, an “organicpolymer” is a polymer that includes carbon atoms in the polymerbackbone, but may also include other atoms either in the polymerbackbone and/or in side chains extending from the polymer backbone(e.g., oxygen, nitrogen, sulfur, etc.).

The “number average molecular weight” (M_(n)) is readily calculated byone of ordinary skill in the art, and generally refers to the ordinaryarithmetic mean or average of the molecular weights of the individualmacromolecules. It is determined by measuring the molecular weight of npolymer molecules, summing the weights, and dividing by n, such asrepresented in the formula:

${\overset{\_}{M}}_{n} = \frac{\sum\limits_{i}{N_{i}M_{i}}}{\sum\limits_{i}N_{i}}$

where N_(i) is the number of molecules of molecular weight M_(i). Thenumber average molecular weight of a polymer can be determined by gelpermeation chromatography, viscometry (Mark-Houwink equation), and allcolligative methods, like vapor pressure osmometry or end-groupdetermination.

The “weight average molecular weight” (M_(w)) is readily calculated byone of ordinary skill in the art, and generally refers to:

${\overset{\_}{M}}_{u} = \frac{\sum\limits_{i}{N_{i}M_{i}^{2}}}{\sum\limits_{i}{N_{i}M_{i}}}$

where N_(i) is the number of molecules of molecular weight M_(i). Theweight average molecular weight can be determined by light scattering,small angle neutron scattering (SANS), X-ray scattering, andsedimentation velocity.

The polydispersity index (PDI) is a measure of the distribution ofmolecular mass in a given polymer sample. The PDI calculated is theweight average molecular weight divided by the number average molecularweight. It indicates the distribution of individual molecular masses ina batch of polymers. The PDI has a value equal to or greater than 1, butas the polymer chains approach uniform chain length, the PDI approachesunity (i.e., 1).

As used herein, the prefix “nano” refers to the nanometer scale (e.g.,from about 1 nm to about 999 nm). For example, particles having anaverage diameter on the nanometer scale (e.g., from about 1 nm to about999 nm) are referred to as “nanoparticles”. Particles having an averagediameter of greater than 1,000 nm (i.e., 1 μm) are generally referred toas “microparticles”, since the micrometer scale generally involves thosematerials having an average size of greater than 1 μm.

Chemical elements are discussed in the present disclosure using theircommon chemical abbreviation, such as commonly found on a periodic tableof elements. For example, hydrogen is represented by its common chemicalabbreviation H; helium is represented by its common chemicalabbreviation He; and so forth.

DETAILED DESCRIPTION

Reference now will be made to the embodiments of the invention, one ormore examples of which are set forth below. Each example is provided byway of an explanation of the invention, not as a limitation of theinvention. In fact, it will be apparent to those skilled in the art thatvarious modifications and variations can be made in the inventionwithout departing from the scope or spirit of the invention. Forinstance, features illustrated or described as one embodiment can beused on another embodiment to yield still a further embodiment. Thus, itis intended that the present invention cover such modifications andvariations as come within the scope of the appended claims and theirequivalents. It is to be understood by one of ordinary skill in the artthat the present discussion is a description of exemplary embodimentsonly, and is not intended as limiting the broader aspects of the presentinvention, which broader aspects are embodied exemplary constructions.

Methods are generally provided for the synthesis of π-conjugatedaromatic/heteroaromatic oligomer-containing vinyl monomers, along withmethods of their polymerization via controlled/living radicalpolymerization methods, and the resulting polymers' applications anduses (e.g., as dielectric materials). In various embodiments, anaromatic/heteroaromatic oligomer is attached as the side groups of themonomers and resulting polymers. As explained in greater detail below,the side-chain aromatic/heteroaromatic oligomer-containing polymers caninclude acrylates, methacrylates, styrenes, acrylamides, norbornenes,etc. The present disclosure is further directed to the resultingpolymers and methods of their use.

The presently disclosed methods and materials have the potential formany other polymer systems to be applied in a similar fashion to obtaincontrolled properties. As such, the strategy described herein not onlyoffers the diversity of structures of different monomer and polymersystems, but also tailored properties. Thus, this strategy enablesside-chain π-conjugated aromatic/heteroaromatic oligomer based polymerswith novel properties.

I. Monomers

In one embodiment, methods are generally provided for preparingπ-conjugated aromatic/heteroaromatic oligomer-containing vinyl monomers.As discussed in greater detail below, such vinyl monomers prepared withpendant π-conjugated aromatic/heteroaromatic oligomers can result inpolymer molecules with these oligomers as functional side groups.

Generally, each monomer includes a polymerizable group attached to theπ-conjugated aromatic/heteroaromatic side chain via an organic linkergroup. Referring to the exemplary embodiments shown in FIGS. 1 a-1 e,the each monomer 10 includes a polymerizable group 12 attached to anorganic linker group 14 and a π-conjugated aromatic/heteroaromatic sidechain 16, such that the organic linker group 14 is positioned betweenand covalently links the polymerizable group 12 to the π-conjugatedaromatic/heteroaromatic side chain 16.

a. π-Conjugated Aromatic/Heteroaromatic Oligomer Side Chains

As shown in FIGS. 1 a-1 e, the π-conjugated aromatic/heteroaromatic sidechain 16 includes a first cyclopentadiene ring 18 having X substitutedtherein and covalently attached to the linker group 14. Generally, X canbe a substituted or unsubstituted hetero-atom (i.e., a non-carbon atom).In particular embodiments, the substituted or unsubstituted hetero-atomof X is selected from the group of the IIIA (e.g., B, Al, Ga, In, andTi), IVA (e.g., Si, Ge, Sn, Pb, and Fl), VA (e.g., N, P, As, Sb, andBi), or VIA (e.g., O, S, Se, Te, and Po) family of elements of thePeriodic Table. In one particular embodiment, X is selected from boron(B), silicon (Si), nitrogen (N), oxygen (O), sulfur (S), and phosphorus(P), with the appropriate valence number of hydrogen atoms attached(i.e., two H present if Si; one H if N or P; no H present if O or S,etc.).

A set 19 of second cyclopentadiene rings 20 are covalently attached tothe first cyclopentadiene ring 18. The set 19 is formed by a number (n)of repeating second cyclopentadiene rings 20 covalently bonded togetherin a chain. In particular embodiments, n is an integer of 1 to about 25,such as 1 to about 20 (e.g., about 2 to about 10). As shown, each of thesecond cyclopentadiene rings 20 are substituted with Y within the ringstructure. Generally, Y can be a substituted or unsubstitutedhetero-atom (i.e., a non-carbon atom), which can be the same ordifferent that X in the first cyclopentadiene ring 18. In particularembodiments, the substituted or unsubstituted hetero-atom of Y isselected from the group of the IIIA (e.g., B, Al, Ga, In, and Ti), IVA(e.g., Si, Ge, Sn, Pb, and Fl), VA (e.g., N, P, As, Sb, and Bi), or VIA(e.g., O, S, Se, Te, and Po) family of elements of the Periodic Table.In one particular embodiment, Y is selected from boron (B), silicon(Si), nitrogen (N), oxygen (O), sulfur (S), and phosphorus (P), with theappropriate valence number of hydrogen atoms attached (i.e., two Hpresent if Si; one H if N or P; no H present if O or S, etc.).

A third cyclopentadiene ring 22 is positioned at the terminal end of theπ-conjugated aromatic/heteroaromatic side chain 16 such that the set 19of second cyclopentadiene rings 20 is positioned between the firstcyclopentadiene ring 18 and the third cyclopentadiene ring 22. As shown,the third cyclopentadiene ring 22 is substituted with Z within the ringstructure. Generally, Z can be a substituted or unsubstitutedhetero-atom (i.e., a non-carbon atom), which can be the same ordifferent that X in the first cyclopentadiene ring 18 and/or Y in thesecond cyclopentadiene ring structure 20. In particular embodiments, thesubstituted or unsubstituted hetero-atom of Z is selected from the groupof the IIIA (e.g., B, Al, Ga, In, and Ti), IVA (e.g., Si, Ge, Sn, Pb,and Fl), VA (e.g., N, P, As, Sb, and Bi), or VIA (e.g., O, S, Se, Te,and Po) family of elements of the Periodic Table. In one particularembodiment, Z is selected from boron (B), silicon (Si), nitrogen (N),oxygen (O), sulfur (S), and phosphorus (P), with the appropriate valencenumber of hydrogen atoms attached (i.e., two H present if Si; one H if Nor P; no H present if O or S, etc.).

In particular embodiments, the π-conjugated aromatic/heteroaromaticoligomer side-chain moiety can be five-membered or six-memberedaromatic/heteroacromatic oligomers (in total number, such that n is 3 or4, respectively) and their derivatives, which include both linear andcyclic aromatic/heteroacromatic oligomers, and various fusedaromatic/heteroacromatic oligomers, such as thiophene, pyrrole, furan,selenophene, thiazole, oxazole, imidiazole, benzene, pyridine, indole,benzothiazole, benzothiadiazole dibenzothiophene, carbazole, fluorene,triphenylamine, phthalocyanine and its metal-containing derivatives,porphyrin and its metal-containing derivatives, etc., with repeat unitnumber ranging from 2 to 12, etc.

b. Organic Linker Group

Diverse linker groups 14 can be positioned between the polymerizablegroup 12 (i.e., containing the vinyl group) and the π-conjugatedaromatic/heteroaromatic side chain 16. As shown in the exemplaryembodiments of FIGS. 1 a-1 c and 1 e, the organic linker group 14 can bea simple alkyl chain having a number (m) of repeating carbon atoms (eachwith two hydrogen atoms thereon, i.e., —CH₂—), with m being an integerof 1 to about 50, such as 2 to about 40 (e.g., about 2 to about 20). Inone particular embodiment, m is about 2 to about 12.

Although not shown in the exemplary embodiments of FIGS. 1 a-1 c and 1e, the alkyl chain of the organic linker group 14 can be substitutedwith common substituents found on alkyl chains (e.g., hydroxyl groups,amine groups, etc.).

In the exemplary embodiment of FIG. 1 d, R₂ can be any organic linkagecontaining O or NH and having 1 to 50 carbon atoms, including but notlimited to, substituted (cyclo)alkyl groups, substituted orunsubstituted (hetero)aryl groups, substituted or unsubstitutedheterocyclic groups, etc.

c. Polymerizable Groups

The polymerizable group 12 of the π-conjugated aromatic/heteroaromaticoligomer monomers 10 can include a vinyl group, such as an acrylicgroup, a methacrylic group, a styrenic group, an acrylamide group, or anorbornene group.

For example, FIGS. 1 a and 1 d show exemplary monomers 10 having a(meth)acrylic group forming its polymerizable group 12, with R₁ beingeither H (i.e., an acrylic group) or —CH₃ (i.e., a methacrylic group).

FIG. 1 b shows an exemplary monomer 10 having a (meth)acrylamide groupforming its polymerizable group 12, with R₁ being either H (i.e., anacrylamide group) or —CH₃ (i.e., a methacrylamide group).

FIG. 1 c shows an exemplary monomer 10 having a styrenic group attachedto the linker group 14 via an oxygen atom.

FIG. 1 e shows an exemplary monomer 10 having a norbornene groupattached to the linker group 14 via an ester group.

No matter the particular chemistry of the polymerizable group 12, avinyl group is present and configured for polymerization into apolymeric chain.

d. Exemplary Monomers

FIGS. 1 a-1 e illustrate exemplary embodiments that are generallydiscussed above. In particular, each of the exemplary embodiments showninclude vinyl monomers with aromatic/heteroaromatic oligomer at the endof the pendant group. The linkers between aromatic/heteroaromaticoligomer and vinyl groups can have different lengths ranging from 2carbons to 12 carbons. For example, 2(2,2′:5′,2″-terthien-5-yl)ethylmethacrylate (TTEMA) is prepared by esterification reaction between2(2,2′:5′,2″-terthien-5-yl)ethanol (TTE) and methacryloyl chloride inthe presence of triethylamine in dichloromethane, as shown in FIG. 2 a.Another example is 2(2,2′:5′,2″-terthien-5-yl)ethyl norbornenate(TTENB), which is also prepared by esterification reaction between TTEand 5-norbornene-2-carbonyl chloride under the same experimentalcondition, as demonstrated in FIG. 2 b.

II. Polymerization and Resulting Polymers

In various aspects, methods are generally provided for the preparationof π-conjugated aromatic/heteroaromatic oligomer-containing vinylmonomers (e.g., those described above) and polymers prepared from thesemonomers. In particular, π-conjugated aromatic/heteroaromaticoligomer-containing polymers can be prepared by free radical andcontrolled/living radical polymerization of the vinyl monomers preparedwith pendant π-conjugated aromatic/heteroaromatic oligomers. Polymercompositions include homopolymers, random copolymers, and blockcopolymers (linear copolymer, star copolymers, bottle-brush copolymers,etc.). These polymers have π-conjugated aromatic/heteroaromatic oligomermoiety at the side-chain.

Generally, the polymerization method for the synthesis of π-conjugatedaromatic/heteroaromatic oligomer-containing polymers usescontrolled/living radical polymerization methods to yield polymershaving applications in many fields, such as dielectric materials,optical and electronic materials, nanolithography, etc.

In summary of particular embodiments, methods are provided for preparingπ-conjugated aromatic/heteroaromatic oligomer vinyl monomers andpolymers, wherein:

(i) said π-conjugated aromatic/heteroaromatic oligomer vinyl monomersinclude acrylate monomers, methacrylate monomers, styrene monomers,acrylamide monomers and norbornene monomers that can be polymerized;

(ii) said π-conjugated aromatic/heteroaromatic oligomer side-chainmoiety that can be five-/six-membered aromatic/heteroacromatic oligomersand their derivatives, which include both linear and cyclicaromatic/heteroacromatic oligomers, and various fusedaromatic/heteroacromatic oligomers, such as thiophene, pyrrole, furan,selenophene, thiazole, oxazole, imidiazole, benzene, pyridine, indole,benzothiazole, benzothiadiazole dibenzothiophene, carbazole, fluorene,triphenylamine, phthalocyanine and its metal-containing derivatives,porphyrin and its metal-containing derivatives, etc., with repeat unitnumber ranging from 2 to 12, etc.

(iii) said homopolymers, random copolymers, block copolymers (linearcopolymers, star copolymers, bottle-brush copolymers, etc.) that derivefrom polymerization of π-conjugated aromatic/heteroaromatic oligomervinyl monomers.

(iv) said homopolymers, random copolymers, block copolymers (linearcopolymers, star copolymers, bottle-brush copolymers, etc.) that havecontrollable linkers between the polymer backbone and thearomatic/heteroaromatic oligomer functional group moiety.

(v) said homopolymers, random copolymers, block copolymers (linearcopolymers, star copolymers, bottle-brush copolymers, etc.) that haveapplications as dielectric materials for capacitors.

As shown in the exemplary embodiments of the Examples below, thesynthesis of π-conjugated aromatic/heteroaromatic oligomer based vinylmonomers has been demonstrated. The monomers include acrylic,methacrylic, styrenic, acrylamide and norbornene monomers. FIGS. 1 a-1 eillustrate a general embodiment: vinyl monomers witharomatic/heteroaromatic oligomer at the end of pendant group. Inparticular embodiment, the linkers between aromatic/heteroaromaticoligomer and vinyl groups have different lengths ranging from 2 carbonsto 12 carbons. For example, 2(2,2′:5′,2″-terthien-5-yl)ethylmethacrylate (TTEMA) is prepared by esterification reaction between2(2,2′:5′,2″-terthien-5-yl)ethanol (TTE) and methacryloyl chloride inthe presence of triethylamine in dichloromethane, as shown in FIG. 2 a.Another example is 2(2,2′:5′,2″-terthien-5-yl)ethyl norbornenate(TTENB), which is also prepared by esterification reaction between TTEand 5-norbornene-2-carbonyl chloride under the same experimentalcondition, as demonstrated in FIG. 2 b.

As shown in the exemplary embodiments of the Examples below, thesynthesis of side-chain π-conjugated aromatic/heteroaromaticoligomer-containing polymers has also been demonstrated by free radicalpolymerization and/or controlled/living polymerization methods (RAFT,ROMP, etc., such as those described in U.S. Publication No. 2012/0214950of Tang, et al. filed on Feb. 15, 2012; U.S. Publication No.2012/0041163 of Tang, et al. filed on Aug. 15, 2011; and U.S.Publication No. 2011/0086979 of Tang filed on Oct. 8, 2010, thedisclosures of which are incorporated by reference herein).

For example, TTEMA based homopolymers can be prepared by reversibleaddition fragmentation transfer (RAFT), following the synthetic route byadopting azobisisobutyronitrile (AIBN) as the initiator and cumyldithiobenzoate (CDB) as the transfer agent, as illustrated in FIG. 2(a). Another example is TTENB based homopolymers, which are prepared byring-opening metathesis polymerization (ROMP), using Grubbs III ascatalyst, as displayed in FIG. 2( b). The molecular weight of suchhomopolymers is in the range of 1,000 g/mol to 1,000,000 g/mol. Thesepolymers can be tuned by changing the linkers betweenaromatic/heteroaromatic oligomer and vinyl groups, or by altering thenature of the oligomer and/or the number of the repeat units.

The dielectric properties of the side-chain π-conjugatedaromatic/heteroaromatic oligomer-containing homopolymers have also beencharacterized. For example, two representatives with different molecularweights exhibit favorable dielectric properties, especially the one withrelatively lower molecular weight, possessing a dielectric constant fromabout 11.4 to about 10.2 and a low loss over a broad frequency rangefrom about 10² to about 4×10⁶ Hz, as demonstrated in FIG. 4.Furthermore, the loss tangent for the two polymers is below 0.02 overthe frequency range from about 1000 Hz to about 2 MHz (the loss tangentis in the range of about 0.009 to about 0.018 and about 0.016 to about0.018 for PTTEMA₆₁ and PTTEMA₁₈₀, respectively). Even at 4 MHz, the losstangent are only 0.009 and 0.028 for PTTEMA₆₁ and PTTEMA₁₈₀,respectively, as shown in FIG. 5.

Thus, the methods presented can offer the following key features:

1. π-Conjugated aromatic/heteroaromatic oligomer can be integrated aspart of vinyl monomer units.

2. The π-conjugated aromatic/heteroaromatic oligomer side-chain moietycan be five-/six-membered aromatic/heteroacromatic oligomers and theirderivatives, which include both linear and cyclicaromatic/heteroacromatic oligomers, and various fusedaromatic/heteroacromatic oligomers, with repeat unit number ranging from2 to 12, etc.

3. π-Conjugated aromatic/heteroaromatic oligomer-containing vinylmonomers used for preparation of side-chain aromatic/heteroaromaticoligomer-containing polymers by controlled/living radical polymerizationmethods (RAFT, ROMP, etc.)

a. Acrylic homopolymers; or

b. Methacrylic homopolymers; or

c. Styrenic homopolymers; or

d. Acrylamide homopolymers; or

e. Norbornene hompolymers.

4. Side-chain π-conjugated aromatic/heteroaromatic oligomer-containingrandom copolymers.

5. Side-chain π-conjugated aromatic/heteroaromatic oligomer-containingblock copolymers, including linear copolymers, star copolymers,bottle-brush copolymers, etc.

6. Dielectric properties of such π-conjugated aromatic/heteroaromaticoligomer-containing homopolymers and various copolymers.

The properties of π-conjugated aromatic/heteroaromaticoligomer-containing polymers can be tuned by changing the monomerstructures (the polymerizable vinyl moiety, the linker or thearomatic/heteroaromatic oligomer moieties), compositions of variouscopolymers.

III. Polymer Grafted Nanomaterials

Methods are also generally provided for grafting a π-conjugatedaromatic/heteroaromatic oligomer-containing polymer onto the surface ofnanoparticles (e.g., BaTiO₃ (BT), TiO₂ ZrO₂, calcium copper titanate(CCTO), etc.), carbon nanotubes, graphite, or other suitablenanomaterials. The surface-modification with polymers can beaccomplished by using surface-initiated free radical polymerizationand/or controlled/living polymerization methods. The resulting surfacemodified nanoparticles, nanotubes, and graphite could be used in theformation of nanocomposite materials.

In one embodiment, methods are provided for the surface-initiatedpolymerization of side-chain π-conjugated aromatic/heteroaromaticoligomer-containing polymers onto various nanoparticles, nanotube andgraphite by free radical polymerization and controlled/livingpolymerization methods.

These polymers can be tuned by changing the linkers betweenaromatic/heteroaromatic oligomer and vinyl groups, or by altering thenature of the oligomer and/or the number of the repeat units asdiscussed above.

For example, TTEMA based homopolymers can polymerized onto the surfaceof BaTiO₃ nanoparticles by reversible addition fragmentation transfer(RAFT), following the synthetic route by adopting azobisisobutyronitrile(AIBN) as the initiator and cumyl dithiobenzoate (CDB) modified BaTiO₃nanoparticles as the transfer agent, as illustrated in FIG. 6.

The molecular weight of such polymers can be in the range of about 1,000g/mol to about 1,000,000 g/mol.

a. Nanoparticles:

The presently disclosed methods can be utilized on a variety ofdifferent types of nanoparticles. The nanoparticle may comprise, forexample, natural or synthetic nanoclays (including those made fromamorphous or structured clays), inorganic metal oxides (e.g., silica,alumina, and the like), nanolatexes, organic nanoparticles, etc.Particularly suitable nanoparticles include inorganic nanoparticles,such as silica, alumina, titania (TiO₂), indium tin oxide (ITO), CdSe,barium titanate (BaTiO₃), etc., or mixtures thereof. Suitable organicnanoparticles include polymer nanoparticles, carbon, graphite, graphene,carbon nanotubes, virus nanoparticles, etc., or mixtures thereof.

Nanoparticles, as used herein, means particles (including but notlimited to rod-shaped particles, disc-shaped particles, platelet-shapedparticles, tetrahedral-shaped particles), fibers, nanotubes, or anyother materials having at least one dimension on the nano scale. In oneembodiment, the nanoparticles have an average particle size of about 1nanometer to about 1000 nanometers, preferably 2 nanometers to about 750nanometers. That is, the nanoparticles have a dimension (e.g., anaverage diameter or length) of about 1 to 1000 nm. Nanotubes can includestructures up to 1 centimeter long, alternatively with a particle sizefrom about 2 to about 50 nanometers. Due to their size, nanoparticleshave very high surface-to-volume ratios.

The nanoparticles may be crystalline or amorphous. A single type ofnanoparticle may be used, or mixtures of different types ofnanoparticles may be used. If a mixture of nanoparticles is used theymay be homogeneously or non-homogeneously distributed in the compositematerial or a system or composition containing the composite material.Non-limiting examples of suitable particle size distributions ofnanoparticles are those within the range of about 2 nm to less thanabout 750 nm, alternatively from about 2 nm to less than about 200 nm,and alternatively from about 2 nm to less than about 150 nm.

It should also be understood that certain particle size distributionsmay be useful to provide certain benefits, and other ranges of particlesize distributions may be useful to provide other benefits (forinstance, color enhancement requires a different particle size rangethan the other properties). The average particle size of a batch ofnanoparticles may differ from the particle size distribution of thosenanoparticles. For example, a layered synthetic silicate can have anaverage particle size of about 25 nanometers while its particle sizedistribution can generally vary between about 10 nm to about 40 nm.

In one embodiment, the nanoparticles can be exfoliated from a startingmaterial to form the nanoparticles. Such starting material may have anaverage size of up to about 50 microns (50,000 nanometers). In anotherembodiment, the nanoparticles can be grown to the desired averageparticle size.

b. Attaching an Anchoring Compound to the Nanoparticle:

In certain embodiments, an anchoring compound can be attached to thesurface of the nanoparticle for subsequent attachment of the polymericchain (e.g., via a “grafting-from” or “grafting-to” approach, asdescribed in greater detail below). The anchoring compound is covalentlybonded to the surface of the nanoparticle, either directly or via afunctionalization group.

The particular anchoring compound can be selected based upon the type ofnanoparticle. Generally, the anchoring compound has a functional groupfor further reaction to the polymer chain. For example, an anchoringcompound can have an amino-functionalization attached to the surface ofa nanoparticle. In one embodiment, the amino-functionalization of thenanoparticles (i.e., attachment of amine groups to the nanoparticles)can be achieved through reaction of the nanoparticles with amono-functional silane anchoring compound (e.g.,3-aminopropyldimethylmethoxysilane or3-aminopropyldimethylethoxysilane). Use of a mono-functional silane asthe anchoring compound, such as 3-aminopropyldimethylmethoxysilane or3-aminopropyldimethylethoxysilane, compared to a difunctional ortrifunctional silanes ensures the formation of a monolayer of anchoringagent on the silica surface and helps to prevent particle agglomerationby crosslinking during processing. However, mono-functional,di-functional, and tri-functional silanes are all suitable for use as ananchoring compound in the presently disclosed methods.

No matter the particular silane (i.e., mono-functional, di-functional,or tri-functional, etc.), the ratio of the silane to the nanoparticlesis critical in determining the grafting density. In addition toadjusting the ratio by varying the concentration of the mono-functionalsilane, addition of a small amount of an inertdimethylmethoxy-n-octylsilane can help to partially cover thenanoparticle surface by inert alkyl groups and to help tune the graftingdensity along with helping to prevent aggregation of the nanoparticles.

c. Attaching a Polymer Chain to the Anchoring Compound:

In a preferred embodiment, to prepare the polymer grafted nanoparticles,a RAFT agent is employed for the polymerization of the π-conjugatedaromatic/heteroaromatic oligomer-containing vinyl monomers. Any suitableRAFT agents can be utilized, including those RAFT agents in any of theRAFT classes (e.g., xanthates, dithiocarbamates, trithiocarbonates, anddithioesters).

Two methods can be utilized to form the π-conjugatedaromatic/heteroaromatic oligomer-containing polymer chain extending fromthe nanoparticles via the anchoring compound: a “grafting-from” approachand a “grafting-to” approach. These strategies will be explained in moredetails in the following sections.

i. “Grafting-From” Methods

In one embodiment, the π-conjugated aromatic/heteroaromaticoligomer-containing polymer chain can be formed by polymerizing aplurality of monomers on the anchored RAFT agent attached to theanchoring compound on the surface of the nanoparticle, with theplurality of monomers comprising at least one of the π-conjugatedaromatic/heteroaromatic oligomer-containing vinyl monomers describedabove. This polymerization results in the π-conjugatedaromatic/heteroaromatic oligomer-containing polymer chain beingcovalently bonded to the surface of the nanoparticle via the anchoringcompound.

The particular types of monomer(s) and/or polymerization technique canbe selected based upon the desired polymeric chain to be formed. Forexample, for RAFT polymerization, π-conjugated aromatic/heteroaromaticoligomer-containing vinyl monomers can be polymerized either alone(i.e., substantially free from any other types of monomers) or incombination with a co-monomer.

Thus, the “grafting-from” method involves formation of the π-conjugatedaromatic/heteroaromatic oligomer-containing polymer chain onto theanchoring compound and results in the π-conjugatedaromatic/heteroaromatic oligomer-containing polymeric chain beingcovalently bonded to the nanoparticle via the anchoring compound (and,if present, a first functionalization compound).

ii. “Grafting-To” Methods

Alternatively, the polymeric chain can be first polymerized andsubsequently covalently bonded to the surface of the nanoparticle,either directly or via an anchoring compound (and, if present, afunctionalization compound). Thus, in this embodiment, the polymericchain has been polymerized prior to attachment to the anchoringcompound.

In this embodiment, the polymeric chain is not limited to the type ofpolymerization and/or types of monomer(s) capable of being polymerizeddirectly to the anchoring compound. As such, as long as the polymericchain defines a functional group that can react and bond to theanchoring compound, any polymeric chain can be bonded to thenanoparticle.

For example, when polymerized utilizing a RAFT agent, then a reactiveend group of the polymer chain (i.e., the RAFT agent group) canreact/attach to the anchoring compound.

iii. Reversible Addition-Fragmentation Chain Transfer Polymerization

Reversible Addition-Fragmentation chain Transfer polymerization (RAFT)is one type of controlled radical polymerization. RAFT polymerizationuses thiocarbonylthio compounds, such as dithioesters, dithiocarbamates,trithiocarbonates, and xanthates, in order to mediate the polymerizationvia a reversible chain-transfer process. RAFT polymerization can beperformed by simply adding a chosen quantity of appropriate RAFT agents(thiocarbonylthio compounds) to a conventional free radicalpolymerization.

Typically, a RAFT polymerization system includes the monomer, aninitiator, and a RAFT agent (also referred to as a chain transferagent). Because of the low concentration of the RAFT agent in thesystem, the concentration of the initiator is usually lower than inconventional radical polymerization. Suitable radical initiators can beazobisisobutyronitrile (AIBN), 4,4′-azobis(4-cyanovaleric acid) (ACVA),etc.

RAFT agents are generally thiocarbonylthio compounds, such as generallyshown in Formula 1 below:

where the Z group primarily stabilizes radical species added to the C═Sbond and the R′ group is a good homolytic leaving group which is able toinitiate monomers. For example, the Z group can be an alkyl group, anaryl group (e.g., phenyl group, benzyl group, etc.), a thiol group(e.g., R—S—, with R being H or any suitable organic group, such asalkyl, aryl, etc), an amine group (e.g., R₂N—, with each R group beingindependently H or any suitable organic group, such as alkyl, aryl,etc), an oxy group (R—O—, with R being any suitable organic group, suchas alkyl, aryl, etc), etc. The R′ group can be an organic chainterminating with a carboxylic acid group, a carboxylic derivative, analkyne group, an azide group, an alcohol group, an alkene group, oranother group that is reactive with the functional group of theparticular anchoring compound attached to the nanoparticle. That is, inone particular embodiment, the functional group of the anchoringcompound present on the nanoparticle is reactive with the R′ group ofthe RAFT agent to ensure sufficient covalent bonding therebetween.

As stated, RAFT is a type of living polymerization involving aconventional radical polymerization in the presence of a reversiblechain transfer reagent. Like other living radical polymerizations, thereis minimized termination step in the RAFT process. The reaction isstarted by radical initiators (e.g., AIBN). In this initiation step, theinitiator reacts with a monomer unit to create a radical species whichstarts an active polymerizing chain. Then, the active chain reacts withthe thiocarbonylthio compound, which kicks out the homolytic leavinggroup (R′). This is a reversible step, with an intermediate speciescapable of losing either the leaving group (R′) or the active species.The leaving group radical then reacts with another monomer species,starting another active polymer chain. This active chain is then able togo through the addition-fragmentation or equilibration steps. Theequilibration keeps the majority of the active propagating species intothe dormant thiocarbonyl compound, limiting the possibility of chaintermination. Thus, active polymer chains are in equilibrium between theactive and dormant species. While one polymer chain is in the dormantstage (bound to the thiocarbonyl compound), the other is active inpolymerization.

By controlling the concentration of initiator and thiocarbonylthiocompound and/or the ratio of monomer to thiocarbonylthio compound, themolecular weight of the polymeric chains can be controlled with lowpolydispersities.

Depending on the target molecular weight of final polymers, the monomerto RAFT agent ratios can range from about less than about 10 to morethan about 20,000 (e.g., about 5,000 to about 15,000). Other reactionparameters can be varied to control the molecular weight of the finalpolymers, such as solvent selection, reaction temperature, and reactiontime. For instance, solvents can include conventional organic solventssuch as tetrahydrofuran, toluene, dimethylformamide, anisole,acetonitrile, dichloromethane, etc.

In particular embodiments, the reaction temperature can range from about25° C. to about 100° C., and the reaction time can be from less thanabout 1 h to about 72 h.

The RAFT process allows the synthesis of polymers with specificmacromolecular architectures such as block, gradient, statistical,comb/brush, star, hyperbranched, and network copolymers. Because RAFTpolymerization is a form of living radical polymerization, it is idealfor synthesis of block copolymers. For example, in the copolymerizationof two monomers (A and B) allowing A to polymerize via RAFT will exhaustthe monomer in solution with significantly suppressed termination. Aftermonomer A is fully reacted, the addition of monomer B will result in ablock copolymer. One requirement for maintaining a narrow polydispersityin this type of copolymer is to have a chain transfer agent with a hightransfer constant to the subsequent monomer (monomer B in the example).

Using a multifunctional RAFT agent can result in the formation of a starcopolymer. RAFT differs from other forms of CLPs because the core of thecopolymer can be introduced by functionalization of either the R groupor the Z group. While utilizing the R group results in similarstructures found using ATRP or NMP, the use of the Z group makes RAFTunique. When the Z group is used, the reactive polymeric arms aredetached from the core while they grow and react back into the core forthe chain-transfer reaction.

iv. Deactivating the Butadiene-Derived Polymer Chain:

No matter the method used to attach the polymeric chain to anchoringcompound on the nanoparticle, upon attachment, the polymeric chain is,in one particular embodiment, deactivated to prevent furtherpolymerization thereon.

For example, if the “grafting-from” method was utilized to attach thepolymeric chain to the anchoring compound via polymerization through aCRP technique (e.g., RAFT), a deactivation agent can be attached to, orreacted with, the end of each polymeric chain to inhibit furtherpolymerization thereon. The deactivation agents can be selected basedupon the type of polymerization and/or the type(s) of monomers utilized,but can generally include but are not limited to amines, peroxides, ormixtures thereof.

On the other hand, if the “grafting-to” method was utilized to attachthe polymeric chain to the anchoring compound via attaching a pre-formedpolymeric chain, the polymeric chain can be deactivated after or beforecovalently bonding the polymeric chain to the anchoring compound.Alternatively, the polymeric chain can be deactivated prior tocovalently bonding the polymeric chain to the anchoring compound.

The deactivation of the polymeric chain can be achieved by any suitableprocess. In one embodiment, the polymer chain can be cleaved.Alternatively, the end of the polymer chain can be deactivated. Forexample, when formed via RAFT polymerization, the types of reactionsthat can be used to convert RAFT agents to deactivated end groupsinclude reactions with diazo compounds, reactions with nucleophilicreagents such as primary amines, and reactions with oxidation agentswhich cleave the RAFT agent off the chain end and form an oxidizedsulfur group such as sulfonic acid.

EXAMPLES

Examples of π-conjugated aromatic/heteroaromatic oligomer vinyl monomersand their polymers are described below.

Example 1

This example is to prepare π-conjugated aromatic/heteroaromaticoligomer-containing methacrylic monomers (FIG. 2( a)). A typicalprocedure for the synthesis is described as follows:aromatic/heteroaromatic oligomer terminated with alkyl alcohol moietyand methacryloyl chloride are dissolved in dichloromethane, followed byadding triethylamine dropwise under the protection of nitrogen gas at 0°C. The resulting mixture is stirred at room temperature overnight toyield the monomer TTEMA.

Example 2

This example is to prepare π-conjugated aromatic/heteroaromaticoligomer-containing methacrylic monomer based homopolymers. The monomersare polymerized by controlled/living radical polymerization (RAFT) usingAIBN as initiators and CDB as the RAFT agent. The polymerization ofTTEMA is carried out by the following procedures: in a dry Schlenkflask, TTEMA, CDB and AIBN are dissolved in 1,4-dioxane, followed byfreeze-pump-thaw for several cycles and purging with nitrogen gas. Themixture is heated at 80˜90° C. for 8˜36 h to yield side-chainaromatic/heteroaromatic oligomer-containing homopolymers (FIG. 2( a)).

Example 3

This example is to prepare π-conjugated aromatic/heteroaromaticoligomer-containing norbornene monomers (FIG. 2( b)). A typicalprocedure for the synthesis is described as follows:aromatic/heteroaromatic oligomer terminated with alkyl alcohol moietyand 5-norbornene-2-carbonyl chloride are dissolved in dichloromethane,followed by adding triethylamine dropwise under the protection ofnitrogen gas at 0° C. The resulting mixture is stirred at roomtemperature overnight to yield the monomer TTENB.

Example 4

This example is to prepare π-conjugated aromatic/heteroaromaticoligomer-containing norbornene monomer based homopolymers. The monomersare polymerized by ROMP using Grubbs III as the catalyst. Thepolymerization of TTENB is carried out by the following procedures: in adry Schlenk flask, TTENB and Grubbs III catalyst are dissolved in1,4-dioxane, followed by freeze-pump-thaw for several cycles and purgingwith nitrogen gas. The mixture is heated at 40˜60° C. for 2˜8 h to yieldside-chain aromatic/heteroaromatic oligomer-containing homopolymers(FIG. 2( b)).

Example 5

This example is to prepare π-conjugated aromatic/heteroaromaticoligomer-containing methacrylic based homopolymers grafted onto BaTiO3nanoparticles. The monomers are polymerized by controlled/living radicalpolymerization (RAFT) using AIBN as initiators and CDB-modified BaTiO3nanoparticles as the RAFT agent. The polymerization of TTEMA is carriedout by the following procedures: in a dry Schlenk flask, TTEMA,CDB-modified BaTiO3 nanoparticles and AIBN are dissolved in 1,4-dioxane,followed by freeze-pump-thaw for several cycles and purging withnitrogen gas. The mixture is heated at 80˜90° C. for 8˜36 h to yieldside-chain aromatic/heteroaromatic oligomer-containing homopolymers(FIG. 3).

Example 6

This example is to prepare π-conjugated aromatic/heteroaromaticoligomer-containing block copolymers, PTTEMA-b-PS (FIG. 3). Theprocedures are similar to Example 2 as follows: in a dry Schlenk flask,PTTEMA and AIBN are dissolved in 1,4-dioxane, followed byfreeze-pump-thaw for several cycles and purging with nitrogen gas. Themixture is stirred at 80˜90° C. for 4˜8 h to yield PTTEMA-b-PS diblockcopolymers.

Example 7

As discussed above, Examples 1-5 demonstrate that nano-dipolarπ-conjugated oligomer thiophene-containing polymers exhibit highpermittivity and low dielectric loss over a wide range of frequencies(100 Hz to about 10 MHz), which could be well suited for capacitorapplications requiring high energy density and fast pulse powerresponse.

Recently, aiming at further improving the dielectric performance andenhancing the energy storage capability of the oligomerthiophene-containing polymers, a new strategy was developed to prepare aseries of π-conjugated oligomer containing polymers based nanocompositesby incorporation of hybrid barium titanate (BaTiO₃) nanoparticles withthe polymers. The surface of the nanoparticles was modified with thesame oligomer containing polymers as the matrix via surface-initiatedreversible addition-fragmentation chain transfer (RAFT) polymerization.The advantage of this method is that the insulating oligomer containingpolymer shells have exactly the same chemical structure and surfaceenergy with the matrix, which not only could enhance the dispersion ofBaTiO₃ nanoparticles but also could improve the interfacial adhesionbetween the nanoparticles and polymer matrix. At present, ourpreliminary results demonstrate that the resulting nanocomposite filmsexhibit much improved dielectric properties while maintaining relativelylow dielectric loss. In sum, our novel conjugatedaromatic/heteroaromatic oligomer-containing polymeric materials withsuperior dielectric properties are of great interest due to theirpotential applications as capacitor materials in portable electronicdevices, hybrid electric vehicles, pulse power systems and energystorage.

These and other modifications and variations to the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention, which ismore particularly set forth in the appended claims. In addition, itshould be understood the aspects of the various embodiments may beinterchanged both in whole or in part. Furthermore, those of ordinaryskill in the art will appreciate that the foregoing description is byway of example only, and is not intended to limit the invention sofurther described in the appended claims.

What is claimed:
 1. A π-conjugated aromatic/heteroaromaticoligomer-containing vinyl monomer comprising a polymerizable group, alinker group, and a π-conjugated aromatic/heteroaromatic side chain, andwherein the polymerizable group comprises a vinyl group, and furtherwherein the π-conjugated aromatic/heteroaromatic side chain comprises: afirst cyclopentadiene ring covalently attached to the linder group andhaving substituted or unsubstituted first hetero-atom substitutedtherein; a set of second cyclopentadiene rings covalently attached tothe first cyclopentadiene ring, wherein the set comprises a number (n)of repeating second cyclopentadiene rings covalently bonded together ina chain, with n being an integer of 1 to about 25, and wherein each ofthe second cyclopentadiene rings has a substituted or unsubstitutedsecond hetero-atom substituted therein; and a third cyclopentadiene ringpositioned at a terminal end of the π-conjugated aromatic/heteroaromaticside chain such that the set of second cyclopentadiene rings ispositioned between the first cyclopentadiene ring and the thirdcyclopentadiene ring, wherein the third cyclopentadiene ring has asubstituted or unsubstituted third hetero-atom substituted therein. 2.The monomer as in claim 1, wherein the polymerizable group comprises anacrylic group, a methacrylic group, a styrenic group, an acrylamidegroup, or a norbornene group.
 3. The method as in claim 1, wherein n is2 to
 12. 4. The method as in claim 1, wherein n is 3 or
 4. 5. Themonomer as in claim 1, wherein the monomer has the structure:

where R₁ is H or —CH₃; X is a substituted or unsubstituted hetero-atom;Y is a substituted or unsubstituted hetero-atom; Z is a substituted orunsubstituted hetero-atom; m is an integer of 1 to about 50; and n is aninteger of 1 to about
 25. 6. The monomer as in claim 1, wherein themonomer has the structure:

where R₁ is H or —CH₃; X is a substituted or unsubstituted hetero-atom;Y is a substituted or unsubstituted hetero-atom; Z is a substituted orunsubstituted hetero-atom; m is an integer of 1 to about 50; and n is aninteger of 1 to about
 25. 7. The monomer as in claim 1, wherein themonomer has the structure:

where X is a substituted or unsubstituted hetero-atom; Y is asubstituted or unsubstituted hetero-atom; Z is a substituted orunsubstituted hetero-atom; m is an integer of 1 to about 50; and n is aninteger of 1 to about
 25. 8. The monomer as in claim 1, wherein themonomer has the structure:

where X is a substituted or unsubstituted hetero-atom; Y is asubstituted or unsubstituted hetero-atom; Z is a substituted orunsubstituted hetero-atom; m is an integer of 1 to about 50; and n is aninteger of 1 to about
 25. 9. A method of forming a polymer, the methodcomprising: polymerizing the π-conjugated aromatic/heteroaromaticoligomer-containing vinyl monomer of claim 1 via a controlled/livingradical polymerization method.
 10. The method as in claim 9, wherein thepolymerizable group comprises an acrylic group or a methacrylic group,and wherein the controlled/living radical polymerization method is aRAFT polymerization method where the π-conjugatedaromatic/heteroaromatic oligomer-containing vinyl monomer is polymerizedin the presence of a RAFT agent.
 11. The method as in claim 9, whereinthe π-conjugated aromatic/heteroaromatic oligomer-containing vinylmonomer is polymerized without any other monomer present such that ahomopolymer is formed.
 12. The method as in claim 9, wherein theπ-conjugated aromatic/heteroaromatic oligomer-containing vinyl monomeris polymerized with another co-monomer present such that a copolymer isformed.
 13. The method as in claim 12, wherein the copolymer is a randomcopolymer or a block copolymer.
 14. A method of grafting a π-conjugatedaromatic/heteroaromatic oligomer-containing polymer onto a surface of ananomaterial, the method comprising: polymerizing the π-conjugatedaromatic/heteroaromatic oligomer-containing vinyl monomer of claim 1 inthe presence of an anchored nanomaterial, wherein the anchorednanoparticle comprises an anchoring group attached the surface of thenanomaterial, and wherein polymerization is performed via a free radicalpolymerization or a controlled/living polymerization method.